first of all, there are endogamous mating practices in all directions in pakistan: people marrying within their ethnic group (sindhi, balochi, punjabi); people marrying within their religion (muslim, sikh, christian); people marrying within their religious sect (sunni, shia); people marrying within their clan/tribe and/or caste (biradaris or zats or quoms) — like i could keep track of this all. *facepalm*

and then, of course, pakistanis are also endogamous within their extended families (or clans) and regularly marry cousins, fbd marriage being the preferred form (you’re not surprised, are you?).

i posted yesterday that one researcher found that pakistanis in britain had an endogamous marriages rate (that included marriages ranging from first-cousins to simply within the same biradari or patrilineage) of 87%. the numbers are not all that different for pakistanis back in pakistan: one researcher (see below) found in 2004-05 that 90% of marriages in punjab and sindh were between blood relatives or members of the same biradari. that’s a LOT of endogamy.

there’s a lot of data out there on consanguineous marriages in pakistan. below are some snippets from just five different articles, including one on sikhs who appear to have a much lower cousin-marriage rate than pakistani muslims (we’ve seen this before). and, interestingly, the sikhs in the particular study cited below did not have any fbd marriage.

christians also have lower cousin-marriages rates than muslims; and hindus have very low rates as well. also, it appears that the number of consanguineous marriages has increased over the past generation or two. (same pattern for pakistanis in the u.k.) seems things are going from bad to worse.

– study of one extended family, up to seven generations, in badin district, sindh, pub. 2010:

“The recent ‘Pakistan Demographic and Health Survey (DHS) has shown that two-thirds of marriages in Pakistan are consanguineous…. The studies by Hussain R et al on consanguineous marriages in Pakistan have show frequency of 58.7% in the Karachi survey and 62.7% in the DHS. 83.6% of consanguineous marriages in the Karachi survey and 80.4% in the DHS were between first cousins.”
_____

@g.w. – “IIRC the base populations of Pakistan and Northern India are similar so i wouldn’t be surprised if this difference was behind their very different trajectories since independence.”

could very well be. i’m not sure about the base population part, either, but you can see the fundamental differences in consanguinity between the two regions by looking at the consang.net map. northern india’s inbreeding rates look like they fall somewhere in the 1-4% to10-19% ranges — not at all like pakistan which, as we’ve seen, is well over 50% (i.e. what the map says).

j said: “chick, it would be interesting to see some statistics about genetic diseases in deeply inbred populations like those Pakistanis you mention. They should look like Charles II of Spain, the drooling imbecile that inherited the Habsburg Empire, but they dont. How much inbreeding depresses their mental and physical capabilities?”

well, the thing about inbreeding is, if i understand it correctly, any possible effects from the inbreeding will only be as good or bad as the genes your groups starts off with — and/or any mutations that might pop up in the group’s gene pool. so, if you’re a group with, say, really high iq genes (whatever they are), it might be quite ok to keep inbreeding ’cause you’ll just hang on to those high iq genes and not introduce any lower iq ones from outside your gene pool. if at some point, tho, someone in your little inbreeding gene pool winds up (via mutation, for instance) with a gene for some horrible, debilitating condition, then your group could be screwed ’cause, if you keep inbreeding, that gene will spread through your group.

some strong inbreeding could, therefore, actually serve to purge very deleterious genes from a population’s gene pool, ’cause those lines that have the very bad genes will just die out and the genes will not really be spread to other lines.

having said that, there are, in fact, a lot of debilitating conditions in pakistan that are connected to inbreeding. if you poke around google scholar, you’ll find quite a bit of research into the subject of the effects of inbreeding on the pakistan population (here’s one example). in fact, the reason that there is so much data on inbreeding throughout the muslim world is precisely because of the health effects in these populations. they really do have some serious genetic disorders in places like saudi arabia.

whether or not all of the inbreeding has had an effect on iq — i dunno. doesn’t seem unlikely to me. there have been some studies (well, one anyway) finding a correlation between the two.

j also said: “Many peoples discovered that inbreeding causes birth defects and they imposed social rules to avoid it. How is that these Pakistanis are not aware of the danger and on the contrary, they enforce it?

“In the case of the Beduins of the Negev, they were living in permanent war of all against all and they had no social mechanism to interact peacefully with anyone, so they were forced to stay in the family. But Pakistanis are a large group and they dont need to fear their neughbors.”

i actually have an article about one village in pakistan which was surveyed to find out what the people there know or don’t know about the potential bad side-effects of inbreeding, but i haven’t read it yet so i don’t know what the researchers found out. (^_^) i’ll have a look at it and see what they discovered.

there are some cultural “solutions” to the problems facing those pakistanis who are, if this is the right word, “victims” of too much inbreeding. there are the unfortunate “rat people” of pakistan, for instance, who exhibit microcephaly (really small brains). they are apparently considered somewhat holy and are kept as sorta revered individuals in mosques or temples. i was going to post this video yesterday, but i actually couldn’t manage to watch it ’cause it was too depressing for me (i am a chick — got some girlie sentimentalities).

regarding your second point — the bedouins vs. the pakistanis — the pakistantis picked up father’s brother’s daughter marriage from the arabs during the eighth century caliphate. they were, presumably, trying to emulate their arab overlords who must’ve seemed pretty cool since they had conquered much of pakistan — and everywhere else from morocco to afghanistan! these accidents of history do happen! (^_^)

well, the thing about inbreeding is, if i understand it correctly, any possible effects from the inbreeding will only be as good or bad as the genes your groups starts off with — and/or any mutations that might pop up in the group’s gene pool. so, if you’re a group with, say, really high iq genes (whatever they are), it might be quite ok to keep inbreeding ’cause you’ll just hang on to those high iq genes and not introduce any lower iq ones from outside your gene pool.

Well, if Cochran, Hawks and Harpending are right, heterozygote advantage is an overlooked area and inbreeding would create an artificially high number of homozygotes, so in addition to the background mutation load, which is very hard to ignore, the lessening of heterozygote advantage (and encouragement of homozygosity in alleles that are only truly damaging if homozygous) could be an issue as well.

@r.a. – “…the lessening of heterozygote advantage (and encouragement of homozygosity in alleles that are only truly damaging if homozygous) could be an issue as well.”

interesting! i wonder how big an issue this is? hapending said over there: “If there would be an advantage to modulating the effect of a locus, an easy quick fix is to break an allele.” do we (meaning they!) have any idea how frequent such “quick fixes” are? is this known, or is this one of those known unknowns?

@r.a. – “…so in addition to the background mutation load, which is very hard to ignore….”

sure. my scenario of a group of inbreeding high-iq folk would clearly not work to infinity and beyond (’cause of mutations and other possible changes to their genomes over time).

Islam is the sole cause of the devastation in Pakistan. Among many other crimes,it encourages consanguinity to harness the aggression to use towards its political ends.thus an area which is the home of some great intellectual attainments is now a dumbed down source of suicide bombers.
Outmarriage is possible only if the security of women is assured. Islam has forced Hindus to keep women seggregated and “protected” which has resulted in all sorts of evil practices and it’s costly genetic and memetic consequences. Islamists used rape as a weapon in India which simply eliminated women from moving out of home at all,let alone size up prospective mates;whereas previously Hindu marriages were dependent on the man and wife,now the family had to step in to provide the security and ensure the survival of the match through dowries.Punjabi women especially were known for the freedom they enjoyed and subterranean Hindu customs continued till the wahabization of Pakistan in th 1980’s.
In modern times Hindu women have gone back to their old ways,though it is not to the advantage of their parent population as previously.